Apparatus for separating electrolysis bath residues on precalcined anodes

Abstract

The invention relates to an apparatus for carrying out a process for separating electrolysis bath residues on used anode units removed from electrolysis cells for the production of aluminum by the Hall-Heroult process, said units comprising a cabon residue 5 or "butt", in which are sealed discs 3 interconnected by flanges 2 welded to a suspension rod 13, the axes of the discs 3 being parallel to the axis of the suspension rod 13, said process comprising passing at least one rotary milling cutter 9, of which the axis of rotation 10 in the working position is substantially parallel to the axis of the rod 13, through the space situated between the discs and around the discs 3 and defined by the upper face of the carbon butt 5 on the one hand and the flanges 2 on the other hand.

We claim: 
     
       1. An apparatus for removing electrolysis bath residues from at least one used anode unit removed from an electrolysis cell for the production of aluminum by the Hall-Heroult process, wherein said at least one anode unit comprises a carbon residue, a plurality of studs sealed within said carbon residue, a suspension rod having flanges welded thereon, said flanges interconnecting said studs, and electrolysis bath residues on the surface of said unit, said apparatus comprising gripping and positioning means for said at least one anode unit including two arms having clamping jaws engagable with said suspension rod, means pivotally supporting said arms for swinging in a plane, a rotary milling cutter having an axis of rotation substantially parallel to the axis of said suspension rod, gripping and moving means for said rotary milling cutter comprising at least one pivotal arm located in a plane substantially transverse to the plane of said two pivotal arms, hooding means for collecting and extracting dust, and means for conveying the removed electrolysis bath residues, wherein the position of said cutter with respect to said anode unit is movable enabling said rotary milling cutter to pass successively between the studs and around the studs. 
     
     
       2. An apparatus as claimed in claim 1, wherein the rotary milling cutter means comprises at least one rotary tool which is provided around its periphery with a plurality of teeth made of a hard material resistant to abrasion and impact. 
     
     
       3. An apparatus as claimed in claim 2, wherein the teeth are removable and replaceable. 
     
     
       4. An apparatus as claimed in claim 2 or 3, wherein the teeth are made of a material selected from carbon steels, alloyed steels, hard refractory materials: carbides, nitrides, carbonitrides, diamonds, either solid or in the form of separate layers. 
     
     
       5. An apparatus as claimed in claim 1, wherein the milling cutter means comprises at least one rotary cutter which passes successively through the space between the studs and around the studs. 
     
     
       6. An apparatus as claimed in claim 1, wherein the milling cutter means comprises a plurality of cutters which pass simultaneously through the space between the studs and around the studs.